Method and apparatus for preparing the ends of cables for splicing

ABSTRACT

To prepare a multi-conductor jacketed cable for splicing it is necessary to remove the jacket for some distance from the end of the cable and to cut the conductors so that they extend for different distances from the end of the jacket. This is done by first gripping the cable by a clamp some distance from its end. Longitudinally spaced pairs of cutters are then brought together to cut through the conductors and through the jacket to the conductors with the cut through the conductors being spaced toward the clamp from the end of the cable a greater distance than the cut through the conductors. The clamp is then moved away from the cutters so as to pull the main portion of the cable with it while leaving the portions of the jacket and conductors between the cutters and the end of the cable behind.

United States Patent 1191 Abarotin Jan. 22, 1974 [75] Inventor: EugeneV. Abarotin, Franklin Twp., A

Westmoreland County, Pa.

[7 3] Assignee: United States Steel Corporation,

Pittsburgh, Pa.

[22] Filed: Apr. 12, 1972 [21] Appl. No.: 243,331

Primary Examiner-Donald G. Kelly Assistant Examiner-Roscoe V. ParkerAttorney, Agent, or Firm-Donald S. Ferito [5 7] ABSTRACT To prepare amulti-conductor jacketed cable for splicing it is necessary to removethe jacket for some distance from the end of the cable and to cut theconductors so that they extend for different distances from the end ofthe jacket. This is done by first gripping the cable by a clamp somedistance from its end. Longitudinally spaced pairs of cutters are thenbrought together to cut through the conductors and through the jacket tothe conductors with the cut through the conductors being spaced towardthe clamp from the end of the cable a greater distance than the cutthrough the conductors. The clamp is then moved away from the cutters soas to pull the main portion of the cable with it while leaving theportions of the jacket and conductors between the cutters and the end ofthe cable behind.

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METHOD AND APPARATUS FOR PREPARING THE ENDS F CABLES FOR SPLICING Thisinvention relates to a method and apparatus for preparing the ends ofmulti-conductor jacketed conductors for splicing and more particularlyto mine cables having two conductors and a ground lead. The cablesplicing is generally required to increase its length or because ofdamage to its insulation, conductors or ground leads. Before theconductors can be joined, a part of the cable jacket must be removed,the conductors and ground leads cut to proper lengths, and theinsulation removed from the ends of the conductors. Two conductor endswith the same polarity are then inserted into a copper sleeve from theopposite ends and the ends of this sleeve are crimped, thus joining thepreviously severed conductors. By insulating the conductors from eachother and from the ground lead, and putting a jac keting material aroundthem all, the splice is completed.

Usually the jacket has been removed by means of a penknife and theconductors have been cut with pliers. Stripping with a penknife is verydifficult and often results in damaging the conductor insulation. Thisdamage may remain unnoticed and may resultin a short circuit. Theconductors, after crimping, must be of the same length since otherwisethe short conductor will take the total tension applied to the cable andmay break. It is very difficult to cut the conductors with hand tools toobtain this equal length.

It is therefore an object of my invention to provide apparatus whichwill accurately out each conductor and ground lead of a jacketedmulti-conductor cable to a predetermined length.

Another object is to provide such apparatus which will also accuratelystrip the jacket from a predetermined portion of the cable withoutdamaging the conductor insulation.

Still anotherobject is to provide a method of cutting the conductors ofa jacketed rnulti-conductor cable to predetermined lengths and at thesame time removing the jacket from a predetermined portion of the cablewithout damaging the conductor insulation.

These and other objects will be more apparent after referring to thefollowing specification and attached drawingsyin which:

FIG. 1 is a side elevation of the apparatus of my invention;

FIG. 2 is a top plan view of FIG. 1',

FIG. 3 is a view taken on the line III-III OF FIG. 1;

FIG. 4 is a view taken on the line IV--IV of FIG. 2 with parts removedso as to show only the die block;

FIG. 5 is a sectional view of a cable to be prepared;

FIG. 6 is a perspective view of a prepared cable;

FIG. 7 is a view of the ground cutting blade;

FIG. 8 is a view of a cutting blade;

FIG. 9 is a view taken on the line lX-IX of FIG. 2;

FIG. 10 is a view taken on the line X-X of FIG. 2.

Referring more particularly to the drawings, reference numeral 2indicates a table top for supporting step cutter 4 and cable stripper 6of my invention. Step cutter 4 includes a base plate 8 attached by meansof bolts 10 to table top 2. Transversely spaced apart vertical plates 12welded to plate 8, have aligned openings 14 therethrough. The top ofeach plate 12 has spaced lugs 16 extending upwardly with alignedcircular holes 18 therethrough. A cover plate 20 has similar lugs 22 oneach end which are received between lugs 16. Holes 24 in lugs 22 arealigned with the holes 18 so as to receive pins 26 and 28. Pin 26 servesas a pivot for the cover plate 20 while pin 28 has a transverse pin 30attached to one end so as to facilitate its removal when it is desiredto swing the cover plate 20 into inoperative position. The foregoingforms a housing 31.

As best shown in FIG. 3 a fluid cylinder 32 extends upwardly through andis threaded into a hole in plate 8. A piston rod 34 mounted in cylinder32 has a pressure plate 36 secured to its upper end above plate 8.

A step cutter die block 38 is mounted on plate 36 in housing 31 betweenplates 12. The die block 38 includes bottom blade plate 40, top bladeplate 42, and intermediate guide plates 44 mounted on four vertical rods46. Plate 42 is secured to each rod 46 between shoulder 48 and washer 50by means of capscrew 52 threaded into the top of the rod. Downwardmovement of plate 40 is limited by means of washers 54 held in place bymeans of capscrews 56 threaded into rods 46. Plates 44 are heldassembled together so that they can be considered a single plate. Twosprings 58 surround each rod 46, one bearing against the top of plate 40and the bottom of lower intermediate plate 44 and the other bearingagainst the top intermediate plate 44 and the bottom of plate 42. Setsof spring 58 and spring 60 are similarly positioned in four locationsbetween the rods 46. The springs 58 and 60 are precompressed at assemblyto support plates 44 with its cable guide opening 62 centered betweenplates 40 and 42 as best shown in FIGS. 3 and 4.

One type of cable C with which my device may be used includes arectangular ground wire G, two conductor strands S, each surrounded by aplastic insulator P, and a. rubber jacket J. For this cable the opening62 will be shaped as shown. The remaining parts of the die block 38 willalso be described with reference to this cable.

As best shown in FIG. 9 the bottom plate 40 supports a notching blade64, a ground cutting blade 66, and two conductor cutting blades 68. Inlike manner the top plate 42 supports a notching blade 64, a groundcutting blade 66, and two conductor blades 68 which are positionedtocooperate with the corresponding blades in the bottom plate. It will beseen that each blade 64 has a curve cutting surface 64S (FIG. 4) of lesswidth than the width of cable C, but of slightly greater width than thedistance between the outside of insulated conductors S so that thejacket J will be cut but the conductors and their insulation will not becut. Each blade 66 has a cutting surface 66S (FIG. 7) of such dimensionthat the blades 66 will cut through ground G without cutting conductorsS or their insulation. Each blade 68 has a cutting surface 68S (FIG. 8)of such dimension that each set of blades 68 will cut through one of theconductors S without cutting ground G or the other conductor S. Thespacing, configuration and size of the blades depends upon the size andconstruction of the cable. Hydraulic fluid is preferably provided forcylinders 32 and 83 by means of a manually operated pump (not shown).

The cable stripper 6 is positioned adjacent the end of step cutter 4having the notching blades 64. The stripper 6 includes a base 70 formedof two end plates 72 and 74 connected by and welded to side plates 76.Plate 72 has a horizontal flange 78 secured thereto which rests on plate8 and is secured thereto by means of capscrews 80. A horizontal fluidcylinder 83 is positioned within base 70 and secured thereto by means ofplate 84 and capscrews 86 and plate 74 has horizontal flanges 81 securedthereto which rest on table top 2 and is secured thereto by means ofbolts 82. Piston rod 88 extends from the right hand end cylinder 83(FIG. 1) and has an upwardly extending link 90 secured thereto by meansof nut 91. Two parallel spaced apart horizontal rods 92 extend betweenand are fastened to plates 72 and 74. A clamp carrying block 94 isslidably mounted on rods 92 and is connected to link 90 by means of ahorizontal pull rod 96 journaled in the plate 74 between rods 92. Theend of rod 96 remote from link 90 is connected to block 94 by pin 98. Asbest shown in FIG. the block 94 has a recess 100 for receiving a bottomknurled gripping jaw 102. Spaced apart flanges 104 at the upper end ofblock 94 receive a lug 106 of a clamping cover 108. A pin 110 passingthrough aligned holes in flanges 104 and lug 106 pivotally connect cover108 to block 94. The cover 108 has a top knurled gripping jaw 111received in recess 112. When the jaws are closed they form an opening inline with opening 62 for receiving cable C. Toggle mechanism 114 mountedon block 94 moves clamping cover 108 downwardly about pivot pin 110 toclamp cable C in position.

In operation, with the clamping cover 108 open the end of a cable C ispassed into and through opening 62 from the right side (FIG. 1) and laidon gripping jaw 102. The cover 108 is then closed firmly grip the cableC between jaws 102 and 111. Fluid is then delivered into the bottom ofcylinder 32 thus raising plate 36 to move plates 40 and 44 upwardly andcompressing springs 58 and 60. This movement continues until the bladeshave penetrated the jacket J to the proper depth and the ground G andconductors S have been severed by blades 66 and 68. Fluid is thendelivered into the left end (FIG. 1) of cylinder 83 to push its rod 88away from the step cutter 4. This moves the clamping block 94 in thesame direction, thus pulling the group G and conductors S out of thatportion of the jacket S to the left of blades 64. The clamping cover 108is then opened and then piston rods 34 and 38 returned to their originalposition. The cable C is removed with its ends being as shown in FIG. 6.The end of a second cable is then prepared in the same manner; theinsulation stripped from the conductor ends, connectors positionedaround the conductors and crimped thereto, the ends of the conductorsinsulated, and a new jacket placed about the joint to complete thesplice. It will be seen that the cutters can be replaced by othercutters or the entire die block 38 easily removed and replaced by ablock of different design for use with other types of cables.

While one embodiment of my invention has been shown and described, itwill be apparent that other adaptations and modifications may be madewithout departing from the scope of the following claims.

I claim:

1. Apparatus for cutting conductors of a multiconductor cable todifferent lengths and stripping a jacket from the end of the cable whichcomprises a support; a step cutter mounted on said support, said stepcutter including a housing, a die block mounted in said housing andhaving two sets of opposed blade supports, means mounting a plurality oflongitudinally spaced apart blades in each of said blade supports toprovide a plurality of pairs of cooperating blades, one pair of saidblades being located adjacent one end of said die block and beingadapted to cut through said jacket, the other pairs of said blades beinglongitudinally spaced from each other and located away from said end ofsaid die block; each pair being also transversely spaced from oneanother and adapted to cut through one of said conductors, means forsupporting said cable between said sets of blades, and means for movingsaid sets of blades together to cut through said jacket to saidconductors and to sever said conductors, and a stripper mounted on saidsupport in longitudinal alignment with said step cutter adjacent saidone end of said die block, said stripper including gripping means forclamping that portion of said cable extending from said step cutter, andmeans for moving said gripping means with said cable clamped thereinaway from said step cutter while said blades are together whereby saidjacket is removed from the end of said cable.

2. Apparatus according to claim 1 in which said blade supports arelocated one above the other, said cable support includes a longitudinalguide opening, and said means for moving said blade supports togetherincludes a fluid motor below said blade supports having a verticalpiston rod and means for supporting the lower blade support on saidpiston rod.

3. Apparatus according to claim 2 in which said die block includes abottom blade plate forming said bottom blade support, a top blade plateforming said top blade support, a guide plate between said blade plateswith said longitudinal guide opening therethrough, a plurality ofvertical rods for supporting said plates for movement toward and awayfrom one another, and a pair of springs around each rod one between thebottom blade plate and the guide plate and the other between the topblade plate and the guide plate.

4. Apparatus according to claim 2 in which said stripper includes a basemounted on said support, a clamp carrying block slidably mounted on saidbase, a fluid motor for moving said block toward and away from said stepcutter, a gripping jaw mounted on said block in general alignment withsaid cable guide opening, a cover pivotally mounted on said block, agripping jaw mounted on said cover, and means for clamping said cover tosaid block with said cable between said gripping jaws.

5. Apparatus according to claim 4 in which said die block includes abottom blade plate forming said bottom blade support, a top blade plateforming said top blade support, a guide plate between said blade plateswith said longitudinal guide opening therethrough, a plurality ofvertical rods for supporting said plates for movement toward and awayfrom one another, and a pair of springs around each rod one between thebottom blade-plate and the guide plate and the other between the topblade plate and the guide plate.

1. Apparatus for cutting conductors of a multi-conductor cable todifferent lengths and stripping a jacket from the end of the cable whichcomprises a support; a step cutter mounted on said support, said stepcutter including a housing, a die block mounted in said housing andhaving two sets of opposed blade supports, means mounting a plurality oflongitudinally spaced apart blades in each of said blade supports toprovide a plurality of pairs of cooperating blades, one pair of saidblades being located adjacent one end of said die block and beingadapted to cut through said jacket, the other pairs of said blades beinglongitudinally spaced from each other and located away from said end ofsaid die block; each pair being also transversely spaced from oneanother and adapted to cut through one of said conductors, means forsupporting said cable between said sets of blades, and means for movingsaid sets of blades together to cut through said jacket to saidconductors and to sever said conductors, and a stripper mounted on saidsupport in longitudinal alignment with said step cutter adjacent saidone end of said die block, said stripper including gripping means forclamping that portion of said cable extending from said step cutter, andmeans for moving said gripping means with said cable clamped thereinaway from said step cutter while said blades are together whereby saidjacket is removed from the end of said cable.
 2. Apparatus according toclaim 1 in which said blade supports are located one above the other,said cable support includes a longitudinal guide opening, and said meansfor moving said blade supports together includes a fluid motor belowsaid blade supports having a vertical piston rod and means forsupporting the lower blade support on said piston rod.
 3. Apparatusaccording to claim 2 in which said die block includes a bottom bladeplate forming said bottom blade support, a top blade plate forming saidtop blade support, a guide plate between said blade plates with saidlongitudinal guide opening therethrough, a plurality of vertical rodsfor supporting said plates for movement toward and away from oneanother, and a pair of springs around each rod one between the bottomblade plate and the guide plate and the other between the top bladeplate and the guide plate.
 4. Apparatus according to claim 2 in whichsaid stripper includes a base mounted on said support, a clamp carryingblock slidably mounted on said base, a fluid motor for moving said blocktoward and away from said step cutter, a gripping jaw mounted on saidblock in general alignment with said cable guide opening, a coverpivotally mounted on said block, a gripping jaw mounted on said cover,and means for clamping said cover to said block with said cable betweensaid gripping jaws.
 5. Apparatus according to claim 4 in which said dieblock includes a bottom blade plate forming said bottom blade support, atop blade plate forming said top blade support, a guide plate betweensaid blade plates with said longitudinal guide opening therethrough, aplurality of vertical rods for supporting said plates for movementtoward and away from one another, and a pair of springs around each rodone between the bottom blade plate and the guide plate and the otherbetween the top blade plate and the guide plate.